Takeup for accommodating slack and tension variations



July 19, 1966 H. EPSTEIN 3,261,566

TAKEUP FOR ACCOMMODATING SLACK AND TENSION VARIATIONS Filed April 17,1964 5 35 Ira/672.371 K United States Patent 0 3,261,566 TAKEUP FURACOMMODATENG SLACK AND TENSEGN VARIATKONS Herman Epstein, Philadelphia,Pa, assignor to Omnitronics, Inc., Philadelphia, Pin, a corporation ofDela- Ware Filed Apr. 17, 1964, Ser. No. 360,508 6 Claims. (Cl. 242-753)The present invention is directed to an energy storage and returnarrangement, and more particularly to such arrangement whichaccommodates tension changes in a rapidly moving strand of material,such as a tape or paper web passing through a photoelectric tape reader.

In the field of tape displacement for automatic reading, printing orother operations, high speeds have been attained, of the order of 500600inches per second. With certain equipment, such as photoelectric tapereaders, it is desired to provide for both continuous reading orcontinuous displacement of the tape, and at other times to selectivelycause intermittent operation, or stepping, of the tape through thesystem. The tape is normally fed to the reader from a tape supply unitsuch as -a reeler, spooler, etc, which generally includes a slacktake-up means such as a spring-biased dancer arm adjacent the outputpoint of the tape supply unit.

Responsive to variations in the amount of slack and/ or the level oftension in the tape at the output point of the reeler, the position ofthe roller at the extremity of the dancer arm is likewise varied (underthe urging of a known bias arrangement) to accommodate the slack and/ ortension variations. It is possible that the dancer arm assembly may havea resonant frequency very close to one of the different frequencies atwhich the tape can be stepped through the reader. For example, if thedancer arm assembly has a resonant frequency of about 30 cycles persecond, and if the tape is stepped through the reader of such system ata frequency near 30 c.p.s., it may happen that after the tape isadvanced and halted in the reader in exact-1y the proper readingposition, a minute fraction of a second later the dancer arm may bounceor move suddenly to take up the slack momentarily created by haltingtape movement through the reader. This bounce may be sufficient todisplace the tape in the reader from the proper reading position, evento the extent of causing double reading at times. Such undesiredmovement and double reading has been noted in tape handling systemswherein the first element in the reader which positively engages thetape is completely stationary, having no resiliency or flexibility toaccommodate the slack or or tension variations occasioned by the bounceof the dancer arm. One known form of tape guide frequently used at theinput point of the reader unit includes a roller or rotatable shaft, butsuch roller rotates about a fixed center and thus can be considered as astationary, inflexible input means for purposes of the presentdescription. In addition to this primary drawback of prior art systems,which causes undesired tape displacement as the dancer arm bounces, asecondary failing of such systems includes the possible breakage ortearing of the tape because of the tension change produced by the bounceof the dancer arm.

It is therefore a primary object of the present invention to provide animproved tape handling unit, for operation with associated units havingslack take-up means, which obviates undesired tape displacement in thetape handling unit which might otherwise be caused by changes in tensionbetween adjacent units.

A more specific object of the invention is the provision, adjacent theinput section of the tape handling unit, of an energy storage and returnarrangement which will "ice accommodate the slack and/or tension changeswithout tape jitter during system operation.

In a preferred embodiment the tape handling unit may be a photoelectrictape reader which receives tape from a reeler or other supply unithaving a slack take-up assembly adjacent its output point. The novel andunobvious energy storage and return arrangement of the present inventionincludes, in one embodiment, a base unit extending from the front panelat substantially right angles. In accordance with an important aspect ofthe present invention, a resilient unit, which may be a cantileverspring, is affixed to the base unit and extends substantially normalthereto, paralleling the front panel of the tape handling unit andaligned with the tape path. With this arrangement the cantilever springhas considerable give or flexure to accommodate the changes in tapetension between the reader and an associated tape supply unit.Accordingly undesired tape movement due to dancer arm bounce issubstantially obviated with the inventive structure.

In order to acquaint those skilled in the art with the best modecontemplated for making and using the invention, a description thereofis set forth in connection with the accompanying drawing, in the severalfigures of which like reference numerals identify like elements, and inwhich:

FIGURE 1 is a front view of a photoelectric tape reader with the presentinvention, and showing a portion of an associated reeler unit;

FIGURE 2 is a bottom view, taken on a scale enlarged with respect tothat of FIGURE 1, depicting a preferred embodiment of the invention;

FIGURE 3 is a sectional showing, taken along the lines 3-3 of FIGURE 2,illustrating certain fastening details of the inventive structure; and

FIGURE 4 is an exploded view depicting components of the inventionbefore assembly.

General system arrangement FIGURE 1 depicts a photoelectric tape reader1'3 and a portion of an associated tape supply unit 45, shown as a tapereeler. Reader unit 10 includes a front panel 11, a. hood or protectivepanel 12 having a pair of flange portions 13 by which the hood isaffixed to the front panel, and other components affixed to the frontpanel 11 of the reader. Reeler 45 has a front panel 46, a fixed tapeguide 47, a dancer arm assembly including a roller 48 extending throughan arcuate slot 50, and a fixed tape guide 51 at the output point of thereeler. Thus the slack takeup means, or dancer arm assembly, ispositioned adjacent the output point of the tape supply unit 45. Thetape or Web 14 is shown passing upwardly from reeler 45 and over a firstenergy storage and return assembly 15, constructed in accordance withthe present invention. This first assembly 15 may be considered theinput point of the reader system. The tape is led through the componentsof a brake assembly 16, under a read head 17, over an adjustable tapeguide 18 and between the rollers of a capstan drive arrangement 20. Atthe opposite side of the reader system, tape 14 passes over anotherenergy storage and return arrangement 15, which may be considered theoutput point of the reader system, to a take-up reel (not shown) of thereeler. With this general perspective of the system including thephotoelectric reader and the locations of the invention, the componentsof the present invention will now be described.

Energy storage and return arrangement As indicated in FIGURE 2, thenovel and unobvious structure of the invention comprises a base unit, orsupport shaft 25, extending outwardly at substantially right angles fromfront panel 11 of the tape handling unit. Support shaft 25 is secured inplace by a member 26, the head portion of which is positioned behind thefront panel and which includes a threaded portion 27 which extendsthrough an aperture of panel 11 and is received in a correspondinglytapped bore of shaft 25. The other end of support shaft 25, the onefarther from reference panel 11, is terminated in a retaining means orcollar 28, of a diameter appreciably larger than that of shaft 25.Annular tape retaining means 28 serves to restrain the moving tape fromdisplacement away from reference panel 11 during system operation.Collar 28 may be a separate unit threaded into, or otherwise affixed to,shaft 25, or may be formed integrally with shaft 25, as was done in thepreferred embodiment.

Affixed to base unit 25 is a resilient unit 30, which in the preferredembodiment was comprised of a cantilever type spring. The springincluded a first arcuate or generally semi-circular end portion 31, alsovisible in FIGURE 4. The central portion 32 of spring 31 issubstantially flat, and the other end portion 33 is curved or arcuate inconfiguration as illustrated. From the showing of FIGURE 1, it isapparent that at the input point of the reader system, tape 14 ispassing upwardly and to the left at an angle with respect to thegenerally horizontal path in the reader system itself. Accordingly, toavoid snags and tearing of the tape, the edge portion 33 of resilientunit 30 is curved as indicated in the drawing.

In the bottom view of FIGURE 2, a pair of fastening screws 34 and 35 areindicated and these screws represent the means for fastening cantileverspring 30 to support shaft 25. As better illustrated in FIGURE 3,fastening screw 35 includes a slotted head portion and a threadedportion which extends through a corresponding aperture of spring 30 andis received in a correspondingly tapped bore of shaft 25. Thisarrangement provides for secure anchoring of the cantilever spring tothe base unit 25. Also indicated in FIGURE 3 is fastening plate 36 whichextends across the width of spring 30 to assist in securing theresilient spring to the support shaft 25.

The exploded view of FIGURE 4 shows the components just described, andfurther indicates the generally flat portion 37 of resilient unit 30which is provided adjacent semi-circular portion 31 of this spring. Theflattened spring portion 37 is positioned adjacent the similarlyflattened surface 38 of support shaft 25, and fastening plate 36 ispositioned adjacent to spring portion 37. Fastening screws 34 and 35 areinserted into tapped bore portions 40 of the support shaft to completethe assembly.

In operation, the stepping or rapid starting and stopping of tapemovement through the system alternately increases and decreases thelevel of the tension forces in tape 14. As these forces increase, spring30 tends to flex or to be displaced in a first direction. 'That is,although end portion 31 of the spring is securely anchored, the otherend portion 33 is deflected downwardly (with reference to FIGURES 1 and4) responsive to increased tension in the tape. With such flexure of thespring, energy is stored in the assembly 15 and thereafter, as thetension forces decrease, end portion 33 of resilient unit 30 isdisplaced upwardly, or in a direction opposite the given direction inwhich it was initially displaced. With this return movement the storedenergy is also returned from the assembly 15. Such operation has greatlyenhanced the reliability of the reader system by substantiallyeliminating tape jitter or undesired movement which has frequently beenoccasioned by bounce of the dancer arm when the tape is stepped at afrequency near the resonant frequency of the dancer arm assembly.

Although only a particular embodiment of the invention has beendescribed and illustrated, it is apparent that modifications andalterations may be made therein. It is therefore the intention in theappended claims to cover all such modifications and alterations as mayfall within the true spirit and scope of the invention.

What is claimed is:

1. In a tape handling system,

a supply unit for delivering tape at an output point,

means including a dancer arm positioned adjacent the output point of thesupply unit for accommodating tension and slack variations in the tape,

a tape processing unit having a reference panel and an input point forreceiving tape from the supply unit, to provide a tape path between theoutput point of the supply unit and the input point of the processingunit, and

means positioned at the input point of said tape processing unit,including a support shaft disposed substantially normal to the panel andto the tape path, and spring means aflixed to said shaft and alignedwith the tape path substantially parallel to said panel, for storingenergy by movement in a given direction as the tape tension increasesand returning energy by movement in a direction opposite said givendirection as the tape tension decreases, whereby the position of thetape in said tape processing unit is not affected by movement of saiddancer arm, thus to insure positive operation of the processing unit.

2. In a tape handling system,

a supply unit for delivering tape at an output point,

a dancer arm positioned adjacent the output point of the supply unit foraccommodating tension and slack variations in the tape,

a tape processing unit having a reference panel and an input point forreceiving tape from the supply unit, to provide a tape path between theoutput point of the supply unit and the input point of the processingunit, and

means positioned at the input point of said tape processing unit,including a support shaft disposed substantially normal to the referencepanel and to the tape path, and spring means having a pair of arcuateend portions and a substantially linear intermediate portion, one ofsaid spring end portions being afiixed to said shaft and saidintermediate portion being aligned with the tape path substantiallyparallel to said panel, for accommodating aberrations in tape tension byrelated flexing of at least a portion of the spring means, whereby theposition of the tape in said tape processing unit is not affected bymovement of said dancer arm, thus to insure positive operation of theprocessing unit.

3. In a tape supplying and reading system,

a tape reeler unit for supplying tape at an output point,

dancer arm means positioned adjacent the output point of the reeler unitfor accommodating tension and slack variations in the tape,

a tape reader unit having a front panel and an input point for receivingtape from the reeler unit, to define a tape path between the outputpoint of the reeler unit and the input point of the reader unit, and

means positioned at the input point of said tape reader unit, includinga support shaft disposed substantially normal to the front panel and tothe tape path, spring means affixed to the shaft and aligned with thetape path for storing energy by flexing as the tape becomes more tautand returning energy by straightening as the tape becomes more slack,and retaining means, afiixed to the end of the support shaft fartherfrom the front panel, for maintaining the tape in said path as the tapepasses over the spring means, whereby the position of the tape in saidreader unit is not affected by movement of the dancer arm, thus toinsure positive operation of the reader unit.

4. An energy storage and return arrangement for the input point of aphotoelectric reader including a front panel and a tape path adjacentsuch panel, tape being received over such path from a tape supply unithaving a dancer arm adjacent its output point, said arrangementcomprising a support shaft affixed to the front panel, extendingsubstantially normal to the panel and to the tape path, and a cantileverspring having at least one arcuate end portion, a second end portion,and a substantially fiat intermediate portion, said second end portionbeing affixed to said shaft and said intermediate spring portion beingaligned with the tape path substantially parallel to said panel in 'aposition to afford tape movement over said arcuate end portion of thespring, for accommodating aberrations in tape tension by related flexingof the cantilever spring about said second end portion, thereby insuringpositive reader operation. 5. An energy storage and return arrangementfor a tape handling unit having a front panel, with tape being receivedfrom a tape supply unit having a dancer arm adjacent its output point,comprising a support shaft affixed to the front panel at substantiallyright angles and aligned with the tape path,

spring means, having one end affixed to the shaft and a central portionaligned with the tape path, for storing energy by displacement in agiven direction as the tape tension increases and returning the storedenergy by movement in a direction opposite said given direction as thetape tension decreases, and

collar means, affixed to the end of the support shaft farther from thefront panel, for maintaining the tape in said path as the tape passesover the spring means, thus to obviate undesired tape movementresponsive to variations in tape tension.

6. For use with a photoelectric tape reader having a front paneladjacent which tape is passed along a given path upon receipt from areeler having a dancer arm adjacent its output point, an arrangement foraccommodating tension variations in the tape and guiding the tape alongsuch path comprising a substantially annular support shaft affixed to,and extending outwardly at substantially right angles from, said panel,said shaft having a flattened portion along the bottom thereof,

a cantilever spring having a first generally semicircular end portionfor extending partially around said shaft, a substantially flatintermediate portion, and an arcuate end portion for receiving tapewithout snagging or tearing at the input point of the reader system,

means for affixing the semi-circular end portion of the spring to thesupport shaft, and

retaining means, of a diameter larger than the diameter of the supportshaft, affixed to the outer end of the support shaft, thereby to retainthe tape in the desired path as the body of the cantilever spring flexesto accommodate tension variations of the tape at the input point to thesystem.

References Cited by the Examiner UNITED STATES PATENTS 2,262,032 11/1941Moore 24275.3 2,732,754 1/1956 Foster et a1. 24255.11 X 2,997,247 8/1961 McGuire et al 24255.12 3,130,936 4/1964 Roehman 24275.3

STANLEY N. GILREATH, Primary Examiner.

MERVIN STEIN, Examiner.

N L. MINTZ, Assistant Examiner.

1. IN A TAPE HANDLING SYSTEM, A SUPPLY UNIT FOR DELIVERING TAPE AT ANOUTPUT POINT, MEANS INCLUDING A DANCER ARM POSITIONED ADJACENT THEOUTPUT POINT OF THE SUPPLY UNIT FOR ACCOMMODATING TENSION AND SLACKVARIATIONS IN THE TAPE, A TAPE PROCESSING UNIT HAVING A REFERENCE PANELAND AN INPUT POINT FOR RECEIVING TAPE FROM THE SUPPLY UNIT, TO PROVIDE ATAPE PATH BETWEEN THE OUTPUT POINT OF THE SUPPLY UNIT AND THE INPUTPOINT OF THE PROCESSING UNIT, AND MEANS POSITIONED AT THE POINT OF SAIDTAPE PROCESSING UNIT, INCLUDING A SUPPORT SHAFT DISPOSED SUBSTANTIALLYNORMAL TO THE PANEL AND TO THE TAPE PATH, AND SPRING MEANS AFFIXED TOSAID SHAFT AND ALIGNED WITH THE TAPE PATH SUBSTANTIALLY PARALLEL TO SAIDPANEL, FOR STORING ENERGY BY MOVEMENT IN A GIVEN DIRECTION AS THE TAPETENSION INCREASES AND RETURNING ENERGY BY MOVEMENT IN A DIRECTIONOPPOSITE SAID GIVEN DIRECTION AS THE TAPE TENSION DECREASES, WHEREBY THEPOSITION OF THE TAPE IN SAID TAPE PROCESSING UNIT IS NOT AFFECTED BYMOVEMENT OF SAID DANCER ARM, THUS TO INSURE POSITIVE OPERATION OF THEPROCESSING UNIT.